Abstract: Flow measurement is strongly influenced by the velocity profile upstream the flowmeter. Flowmeters are designed and calibrated under the condition that the velocity is fully developed, while the disturbance such as swirl, cross-flow and asymmetry will induce the system errors. Mounting conditioner is a effective way for solving this problem. A novel flow conditioner is presented based on computational fluid dynamics(CFD). Flow fields in the horizontal rotameter with and without the scalariform multiple holes conditioner are simulated. In order to testify the efficiency, the conditioner are installed in two different caliber rotameters and the field tests are carried out. In fact , the conditioner in the horizontal floater flowmeter decreases the uncertainty by 0.5%.

Key words: CFD, Conditioner, Rotameter, Uncertainty